Agastache rugosa aka Chinese Giant Hyssop

Agastache rugosa, or Korean mint, belongs to the mint family. Its native range spans the Russian Far East and temperate East Asia. It grows in mountain grasslands, valleys, and near streams. It also grows in sunny meadows with stony soil. Other names include Chinese giant hyssop and wrinkled giant hyssop. This herbaceous perennial forms upright clumps and loses its leaves for winter.

Garden height varies between the sources. NC State gives 1–3 feet [0.3–0.9 metres]. RHS gives a taller range of 2.6–4.9 feet [0.8–1.5 metres]. Reported spread reaches about 1.6–2 feet [0.5–0.6 metres]. The green stems stand upright and have square cross sections. Pairs of pale green leaves grow along them. Each simple leaf has a toothed edge and no hairs. Crushed leaves release a strong scent like licorice or anise.

Purple to lavender flowers grow in spikes above the leaves. They bloom through summer and into fall. NC State places flowering from midsummer to early fall. The flowers have scent and suit use as cut stems. Bees, butterflies, and hummingbirds visit and pollinate them. Plant groups can add color to borders and meadow gardens. The plant also suits cottage gardens, paths, and small spaces. Its blooms support pollinators over a long part of the season.

Grow Korean mint in full sun with shelter from exposure. It needs soil that drains well but accepts several soil types. These include sand, loam, chalk, and well-drained clay. It accepts acid, neutral, and alkaline soils. Soil can range from dry to moist, and plants tolerate drought. NC State lists USDA zones 4–9; RHS rates it H4. Care needs are low, and deer and rabbits tend to avoid it. Most pests cause few problems, though dry summers can bring powdery mildew. Remove faded flower spikes during the season. Raise new plants from seed or divide clumps in spring.

Young leaves can be eaten raw or cooked. Their strong anise taste suits flavoring food and making tea. Some gardeners may find them too coarse for salads. PFAF lists seeds as possibly edible, but gives few details. The plant has a history of use in Chinese herbalism. Traditional uses include digestive complaints; this does not establish clinical benefit. PFAF reports no known hazards, rather than proof of complete safety.